Loading ...

Yet another large database study is tying GLP-1 drugs to potential benefits in cancer, suggesting that some patients prescribed the medications after cancer diagnosis have a significantly decreased rate of progression to metastatic disease.

The study examined real-world data from over 12,000 patients with any of seven cancers associated with obesity, diabetes, or both. It found that among patients with four of those cancers — lung, breast, colorectal, or liver — those prescribed a GLP-1 medication were 38%-50% less likely to progress to stage IV disease than comparable patients prescribed a gliptin diabetes medication.

The findings, presented at the American Society of Clinical Oncology (ASCO) 2026, add to a growing body of evidence linking GLP-1 use to either reduced cancer incidence or improved cancer outcomes.

However, experts stressed the limitations of the data and said it’s too early to prescribe GLP-1s in the hopes of slowing cancer progression.

The analysis should be viewed as “exploratory rather than conclusive,” said lead investigator Mark David Orland, MD, of Taussig Cancer Institute, Cleveland Clinic, in Cleveland.

In an interview with Medscape Medical News, he noted that the dataset spanned roughly a decade beginning in 2015 — a period when cancer therapies evolved substantially. And while the study team tried to adjust for differences in cancer treatments over time, residual confounding remains possible, Orland said.

Still, he believes the findings provide the basis for further investigation in clinical trials.

Real Benefits or Bias?

Interest in the relationship between GLP-1s and cancer has grown rapidly in recent years. Several studies have found that people who use the medications have lower rates of certain cancers, particularly those related to obesity.

Relatively little research has dug into the potential effects of GLP-1 use among patients who already have cancer, but there have been some positive signals. One recent study found that women with breast cancer who used GLP-1s for diabetes had better long-term survival than their peers who used metformin or insulin.

However, those prior studies, like the current one, used electronic health records from large databases. And as previously reported by Medscape Medical News, critics see numerous potential biases in the research. Most importantly, there could be many differences between people prescribed GLP-1s — especially in the initial years after their approval — and people prescribed older, cheaper diabetes drugs.

For the new study, Orland and his colleagues used the TriNetX global database to create a propensity score-matched analysis of 12,112 patients who had one of seven cancers and initiated either a GLP-1 or a gliptin after diagnosis.

Gliptins, or DPP-4 inhibitors, are a class of diabetes medications that typically do not spur weight loss and have a moderate glucose-lowering effect.

Overall, Orland’s team found, GLP-1 use was associated with a statistically significant reduction in metastatic progression in four cancers. The largest effect was seen among patients with non-small cell lung cancer: Metastatic progression occurred in 10% of GLP-1 users vs 22% of gliptin users, for a 50% relative reduction in risk.

The corresponding rates were 10% vs 20% among patients with breast cancer (43% risk reduction); 19% vs 28% among patients with hepatocellular carcinoma (38% risk reduction); and 13% vs 22% among patients with colorectal cancer (31% risk reduction).

There were also “protective trends” among patients with prostate, pancreatic, or kidney cancers, but those differences did not reach statistical significance, Orland told conference attendees.

Most patients in the dataset received GLP-1s for diabetes management, although some qualified through obesity-related indications. To reduce treatment-selection bias, the investigators matched patients on A1c levels and BMI.

When it comes to type 2 diabetes management, metformin has long been the recommended first-line treatment. Asked why gliptins were chosen as the comparator in this study, Orland said that evidence on metformin and cancer progression has been conflicting. He described gliptins as the “cleanest and least biased comparator.”

Not Ready for Prime Time

During an ASCO press briefing, Julie Gralow, MD, a breast medical oncologist at the University of Washington, Seattle, brought up a frequently cited issue with this type of GLP-1 research: People prescribed the drugs may be more plugged into the healthcare system.

She questioned whether the new findings reflect a true drug effect or differences in healthcare engagement among GLP-1 users.

Other physicians at the press briefing fielded the question of whether they would prescribe a GLP-1 to a patient with early-stage cancer with the aim of slowing progression. They said no, at least not yet.

“This is provocative data that we want to be really exploring very carefully,” said ASCO president Eric Small, MD, who co-leads the prostate cancer program at the University of California San Francisco Comprehensive Cancer Center.

At this point, he said, “I’m not convinced that the data is there for prostate cancer.”

Jennifer Ligibel, MD, a breast cancer specialist at Dana-Farber Cancer Institute in Boston, expressed a similar view regarding breast cancer. She described GLP-1s as transformative for weight management but said she would not prescribe one specifically to reduce the risk for cancer progression without more supporting data.

Mahyar Etminan, PharmD, is a senior epidemiologist at Epilytics, a consulting firm that evaluates the quality of epidemiologic studies. He reviewed the study for Medscape Medical News and pointed to some issues with the analysis.

One is the inclusion of cancer screening frequency in the propensity-score matching.

“Although screening frequency may act as a confounder and therefore warrant adjustment, it may also function as a collider,” Etminan said.

He was referring to an important issue in observational research called collider bias, which can create a false association between an exposure and outcome.

In this case, Etminan explained, patients who undergo more frequent screening may be more likely to receive a GLP-1 because they are more engaged with the healthcare system. At the same time, screening intensity itself could influence cancer prognosis, progression risk, or the likelihood of detecting metastatic disease.

In addition, Etminan said it’s unclear whether the researchers performed any lag period or latency analyses to account for occult metastatic disease that may have been present before GLP-1 initiation.

“Additional details on these issues would strengthen the causal interpretation of the findings,” he said.

Ultimately, Gralow pointed out, research will have to move past simply linking GLP-1 prescriptions to cancer outcomes.

“We’ll need a randomized trial to prove causation beyond association,” she said.

The study did not have external funding. Orland disclosed having relationships with Alexion Pharmaceuticals, Bristol Myers Squibb/Celgene, Geron, and Novartis. Gralow reported serving as an advisor for AstraZeneca, Genentech, Immunomedics, and Sandoz. Ligibel, Small, and Etminan had no disclosures.